Process kit de-bubbling

ABSTRACT

In some examples, an electroplating apparatus is provided for depositing a metal layer on a substrate. An example electroplating apparatus comprises a plating cell to receive a plating solution, an electrode, a counter electrode, a substrate holding fixture, a resistive element, and a de-bubbler device supportable rotatably adjacent the resistive element to generate or direct a flow of plating solution through the resistive element to release trapped bubbles.

CLAIM OF PRIORITY

This application claims the benefit of priority to U.S. Provisional Patent Application No. 63/120,078, filed on Dec. 1, 2020, which is incorporated by reference herein in its entirety.

FIELD

The present disclosure relates generally to process kit de-bubbling, and more particularly to process kit de-bubbling in electroplating a metal layer on a semiconductor wafer. In some aspects, the methods and apparatus described herein are ultimately useful for controlling plating uniformity.

BACKGROUND

Typically, when electroplating a metal layer on a semiconductor, bubbles form underneath one or more of the process kit elements in an electroplating cell and become trapped there. One process kit element that can be heavily impacted by this problem is an ionically resistive ionically permeable element positioned adjacent a substrate holder in the cell. The ionically resistive ionically permeable element may also be referred to as a highly resistant virtual anode, or HRVA. Due to the restrictive configuration of the HRVA and process kit, these bubbles do not automatically purge themselves to atmosphere and must be removed by external means.

This approach can present several issues. For example, a manual process is slow, requires the use of full acid personal protective equipment (PPE) due to the chemical exposure risk, and requires great skill and dexterity in finding and removing trapped bubbles.

The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

BRIEF SUMMARY

In some examples, an electroplating apparatus is provided for depositing a metal layer on a substrate. An example electroplating apparatus may comprising a plating cell to receive a plating solution; an electrode; a counter electrode; a substrate holding fixture; a resistive element; and a de-bubbler device supportable rotatably adjacent the resistive element to generate or direct a flow of plating solution through the resistive element.

In some examples, the de-bubbler device is rotatable in use to generate an upward flow of plating solution through the resistive element to remove bubbles trapped thereunder.

In some examples, the de-bubbler device is mountable in the substrate holding fixture.

In some examples, the de-bubbler device includes a wafer-shaped plate.

In some examples, the de-bubbler device includes a flow generation element.

In some examples, the flow generation element includes an impeller.

In some examples, the de-bubbler device includes a flow control element.

In some examples, the flow control element includes a cross-rib.

In some examples, a de-bubbler device is provided for de-bubbling electroplating apparatus. An example de-bubbler device may comprise a back plate, and at least one flow generation element and/or at least one flow control element.

In some examples, the back plate is wafer-shaped and the de-bubbler device is mountable in a substrate support fixture of the electroplating apparatus.

In some examples, the at least one flow generation element includes an impeller.

In some examples, a distal end of the impeller is disposed at or adjacent a periphery of the back plate.

In some examples, the at least one flow control element includes a rib.

In some examples, the electroplating apparatus includes a resistive device, and wherein the at least one flow control element of the de-bubbler device is configured to interact with a flow control element of the resistive device in a clocked position of the de-bubbler device.

In some examples, the at least one flow control element extends fully across the de-bubbler device between peripheral positions on the back plate.

In some examples, the de-bubbler device further comprising a plurality of flow control elements, each flow control element associated with a corresponding, clocked position of the de-bubbler device.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments are illustrated by way of example and not limitation in the views of the accompanying drawing:

FIG. 1 illustrates plating apparatus according to example embodiments.

FIGS. 2-5 are respective pictorial views of the underside of a de-bubbler device, according to example embodiments.

FIG. 6 illustrates aspects of the subject matter in accordance with example embodiments.

FIG. 7 is a sectional view of electroplating apparatus with an example dc-bubbler device supported by a clam-shell holding fixture, according to an example embodiment.

FIG. 8 illustrates a method of depositing a metal layer on a substrate, according to an example embodiment.

FIG. 9 is a block diagram illustrating an example of a machine upon which one or more example embodiments may be implemented, or by which one or more example embodiments may be controlled.

DETAILED DESCRIPTION

The description that follows includes systems, methods, techniques, instruction sequences, and computing machine program products that embody illustrative embodiments of the present disclosure. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of example embodiments. It will be evident, however, to one skilled in the art that the present disclosure may be practiced without these specific details.

A portion of the disclosure of this patent document may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to any data as described below and in the drawings that form a part of this document: Copyright Lam Research Corporation, [date], All Rights Reserved.

Embodiments are described generally where the substrate is a semiconductor wafer; however the invention is not so limited. Provided apparatus and methods are useful for electroplating metals in Through Silicon Via (TSV) and Wafer Level Packaging (WLP) applications, but can also be used in a variety of other electroplating processes, including deposition of copper in damascene features. Examples of metals that can be electroplated using provided methods include, without limitation, copper, silver, tin, indium, chromium, a tin-lead composition, a tin-silver composition, nickel, cobalt, nickel and/or cobalt alloys with each other and with tungsten, a tin-copper composition, a tin-silver-copper composition, gold, palladium, and various alloys which include these metals and compositions.

In a typical electroplating process, the semiconductor wafer substrate, which may have one or more recessed features on its surface is placed into the wafer holder, and its platable (working) surface is immersed into an electrolyte contained in the electroplating bath. The wafer substrate is biased negatively, such that it serves as a cathode during electroplating. The ions of the platable metal (such as ions of metals listed above) which are contained in the electrolyte are being reduced at the surface of the negatively biased substrate during electroplating, thereby forming a layer of plated metal. The wafer, which is typically rotated during electroplating, experiences an electric field (ionic current field of the electrolyte).

In example configurations of the apparatus provided herein the electroplating apparatus includes a plating chamber configured to hold electrolyte, where the plating chamber is separated by an ion-permeable membrane into anolyte and catholyte compartments. An electrode, or primary anode, is housed in the anolyte portion, while the substrate is immersed into the electrolyte in the catholyte portion across the membrane. The compositions of anolyte (electrolyte in the anolyte compartment) and catholyte (electrolyte in the catholyte compartment) can be the same or different.

The membrane allows ionic communication between the anolyte and catholyte regions of the plating cell, while preventing the particles generated at the primary anode from entering the proximity of the wafer and contaminating it. In some embodiments, the membrane is a nanoporous membrane (including but not limited to reverse osmosis membrane, a cationic or anionic membrane) that is capable of substantially preventing physical movement of the solvent and of dissolved components under the influence of pressure gradients, while allowing relatively free migration of one or more charged species contained in the electrolyte via ion migration (motion in response to the application of an electric field). Ion exchange membranes, such as cationic exchange membranes are especially suitable for these applications. These membranes are typically made of ionomeric materials, such as perfluorinated co-polymers containing sulfonic groups (e.g., Nafion), sulfonated polyimides, and other materials known to those of skill in the art to be suitable for cation exchange. Selected examples of suitable Nafion membranes include N324 and N424 membranes available from Dupont de Nemours Co. The membrane separating catholyte and anolyte may have different selectivity for different cations. For example, it may allow passage of protons at a faster rate than the passage rate of metal ions (e.g. cupric ions).

Electroplating apparatus having membrane-separated catholyte and anolyte compartments achieves separation of catholyte and anolyte and allows them to have distinct compositions. For example, organic additives can be contained within catholyte, while the anolyte can remain essentially additive-free. Further, anolyte and catholyte may have differing concentrations of metal salt and acid, due, for example, to ionic selectivity of the membrane. In example configurations of the electroplating apparatus provided herein, a secondary electrode is positioned such that the plating current donated and/or diverted by the secondary electrode is not passed through the membrane separating the anolyte and catholyte portions of the plating chamber.

In example configurations of the apparatus provided herein, the apparatus includes an ionically resistive, ionically permeable element positioned in a close proximity of the substrate in the catholyte compartment of the plating chamber. This allows for free flow and transport of electrolyte through the element, but introduces a significant ionic resistance into the plating system, and may improve center-to-edge (radial) uniformity. In some embodiments, the ionically resistive ionically permeable element further serves as a source of electrolyte flow that exits the element in a direction that is substantially perpendicular to the working face of the substrate (impinging flow), and primarily functions as a flow-shaping element. In some embodiments the element includes channels or holes that are perpendicular to the platable surface of the wafer substrate. In some embodiments the element includes channels or holes that are at an angle that is different from 90 degrees relative to the platable surface of the wafer substrate. A typical ionically resistive ionically permeable element accounts for 80% or more of the entire voltage drop of the plating cell system.

In contrast, the ionically resistive ionically permeable element has very little fluid flow resistance and contributes very little to the pressure drop of the cell and ancillary supporting plumbing network system. This is due to the large superficial surface area of the element (e.g., about 12 inches in diameter or 700 cm²) and modest porosity and pore sizes (e.g. the element may have a porosity of about 1-5%) created by an appropriate number of drilled channels (also referred to as pores or holes) that may have a diameter of about 0.4 to 0.8 mm. For example, the calculated pressure drop for flowing 20 liters/minute through a porous plate having a porosity of 4.5% and thickness of 0.5 inches (e.g., a plate comprising 9600 drilled holes with 0.026″ diameter) is less than 1 inch of water pressure (equal to approximately 0.036 psi). Generally the ionically resistive ionically permeable element may include pores that form interconnecting channels within the body of the element, but in many embodiments it is more preferable to use an element that has channels that do not interconnect within the body of the element (e.g., use a plate with non-interconnected drilled holes). Some embodiments of an ionically resistive ionically permeable element are referred to as channeled ionically resistive plate (CIRP).

The apparatus is also configured such that the flow of the plating fluid backwards through the ionically resistive element is substantially prevented, even when the plating fluid is injected in a direction that is substantially parallel to the surface of the ionically resistive ionically permeable element. It is important to note that motion of incompressible fluids, such as water, involves various levels of scaling and balance of inertial and viscous forces. Considering the fluid dynamic Navier-Stokes equations and the fact that fluid flow behavior is governed by tensor (vector) equations with important inertial terms, one can understand that enabling the plating liquid to flow through the ionically resistive ionically permeable element from a manifold below and “upwards” through it may be facile (since low pressure is required to obtain a substantial amount of flow), but in contrast, fluid flowing parallel to the surface may have very little tendency and a “high resistance” to passing through the porous material at the same static pressure. Changing the direction of movement of fluid at a right angle from rapid movement parallel to the surface to movement that is normal to the surface involves the deceleration of the fluid and viscous dissipation of energy in the fluid, and therefore can be highly unfavorable. Some embodiments of an ionically resistive ionically permeable element are referred to as a highly resistant virtual anode (HRVA). In this specification, an ionically resistive ionically permeable element will generally be referred to as a “resistive element”. This term includes within its ambit a CIRP and an HRVA.

In some examples, plating apparatus includes electroplating process kit. As described more fully below, the process kit may include certain elements and features, for example, a resistive element supported in close proximity to a substrate such as a wafer, and a wafer support element such as a “clamshell” holding fixture. Other process kit elements of an electroplating apparatus are possible. Example plating apparatus may include a membrane separating anolyte and catholyte compartments, and a secondary anode. These are examples of plating apparatus, and it should be understood that the plating apparatus of the present disclosure can be modified within the scope of the appended claims. For example, an annular shield need not be present in all embodiments, and when present, the shield may be positioned below the resistive element, above the resistive element, or can be integrated with the resistive element.

Referring to FIG. 1 , a diagrammatical cross-sectional view of electroplating apparatus 101 is shown. The electroplating apparatus 101 includes a plating cell 103 containing a plating solution, which typically includes a source of metal ions and an acid. A substrate, such as a wafer 105, is immersed into the plating solution and is held by a “clamshell” holding fixture 107, mounted on a rotatable spindle 109, which allows bidirectional rotation of the clamshell holding fixture 107 together with the wafer 105. The holding fixture 107 may include or act as a “counter electrode” or “cathode” that conveys a charge to the wafer 105. An electrode, such as a primary anode 111 (which may be an inert or a consumable anode) is disposed below the wafer 105 within the plating cell 103 and is separated from the wafer region by an anodic membrane 113, preferably an ion selective membrane. The region 115 below the anodic membrane is often referred to as an “anode chamber” or “anolyte compartment” and electrolyte within this chamber as “anolyte”. The region 117 above the membrane 113 is referred to as a “catholyte compartment”. The ion-selective anodic membrane 113 allows ionic communication between the anodic and cathodic regions of the plating cell 103, while preventing the particles generated at the anode from entering the proximity of the wafer and contaminating it and/or undesirable chemical species, present in the catholyte electrolyte, from coming into contact with the anode 111.

The plating solution is continuously provided to plating cell 103 by a pump (not shown). In some embodiments, the plating solution flows upwards through the membrane 113 and an ionically resistive ionically permeable element 119 located in close proximity of the wafer 105. In this specification, the ionically resistive ionically permeable element 119 will be referred to generally as a “resistive element” 119. In some embodiments, such as when the membrane 113 is largely impermeable to flow of the plating solution (e.g., a nanoporous media such as a cationic membrane), the plating solution enters a plating chamber between the membrane 113 and the resistive element 119, for example at the chamber periphery, and then flows through the resistive element 119. In this case, plating solution within the anode chamber may be circulated and the pressure can be regulated separately from the resistive element 119 and the cathode chamber.

In some examples, a secondary anode chamber 121, housing a secondary anode 123, is located on the outside of the plating cell 103 and peripheral to the wafer 105. In certain embodiments, the secondary anode chamber 121 is separated from the plating cell 103 by a wall having multiple openings (a membrane support structure) covered by an ion-permeable membrane 125. The membrane 125 allows ionic communication between the plating cell 103 and the secondary anode chamber 121, thereby allowing the plating current to be donated by the second anode. The porosity of this membrane is such that it does not allow particulate material to cross from the secondary anode chamber 121 to the plating cell 103 and result in wafer contamination. Other mechanisms for allowing fluidic and/or ionic communication between the secondary anode chamber and the main plating cell are within the scope of this disclosure. Examples include designs in which the membrane, rather than an impermeable wall, provides most of the barrier between plating solution in the second cathode chamber and plating solution in the main plating cell. A rigid framework may provide support for the membrane in such embodiments.

Additionally, one or more shields, such as an annular shield 127 (or focus ring) may be positioned within the plating cell 103. Example shields 127 may include ring-shaped dielectric inserts, which are used for shaping the current profile and improving the uniformity of plating. Other shield designs and shapes may be employed. In general, the shields may take on any shape including that of wedges, bars, circles, ellipses, and other geometric designs. The ring-shaped inserts may also have patterns at their inside diameter, which improve the ability of the shields to shape the current flux in the desired fashion. The function of the shields may differ, depending on their position in the plating cell. Example systems of the present disclosure can include any of the static shields, as well as variable field shaping elements.

Two DC power supplies (not shown) can be used to control current flow to the wafer 105, the primary anode 111, and to the secondary anode 123, respectively. Alternatively, one power supply with multiple independently controllable electrical outlets can be used to provide different levels of current to the wafer and to the secondary anode. The power supply or supplies may be configured to negatively bias the wafer 105 and positively bias the primary anode 111 and secondary anode 123. The system further includes a controller, for example the controller 900 of FIG. 9 , which allows modulation of current and/or potential provided to the elements of electroplating cell. The controller 900 may include program instructions specifying current and voltage levels that need to be applied to various elements of the plating cell, as well as times at which these levels need to be changed. For example, it may include program instructions for supplying power to the secondary anode, and, optionally for dynamically varying the power supplied to the secondary anode during electroplating.

Arrows show the plating current in the illustrated apparatus. Current originating from the primary anode 111 is directed upward, passes through the membrane 113 separating anolyte and catholyte compartments and the resistive element 119. Current originating from the secondary anode 123 is directed from the periphery of the plating cell 103 to the center and does not pass through the membrane 113 separating the anolyte and catholyte compartments and the resistive element 119.

As discussed further above, when electroplating a metal layer on a substrate or wafer 105, bubbles can form underneath the resistive element 119. Due to the narrow restrictions within the resistive element 119, these bubbles do not automatically rise up through the resistive element 119 and purge themselves to atmosphere. The bubbles often require removal if their negative effects on wafer processing are to be avoided. Conventionally, such bubble removal has been done manually, for example by using a squeeze bulb pump and tapping tools to agitate and suck out bubbles.

With this and other issues in mind, examples of the present disclosure include a plating solution flow generator, referred to herein as a “de-bubbler device”, generally shown at 102. Examples of the de-bubbler device 102 are described in more detail below. In some examples, the de-bubbler device 102 is mountable in the clamshell holding fixture 107, after a wafer electroplating operation is complete, to de-bubble the resistive element 119. Thus, with respect to the view of FIG. 1 , a wafer 105 and a de-bubbler device 102 may not be present in the plating cell 103 at the same time, or at least during wafer electroplating operations, when the de-bubbler device 102 is in use. The mounting of the de-bubbler device 102 in the clamshell holding fixture 107 allows bidirectional rotation of the de-bubbler device 102 to remove bubbles or generally generate or direct a flow or the plating solution, as described in more detail below.

In some examples, the de-bubbler device 102 is supported in use for rotation closely adjacent an upper surface of the resistive element 119. Appropriate rotation of the de-bubbler device 102 generates a fluid flow, or an upward suction, which entrains or sucks trapped bubbles up through the resistive element 119 where they may be released to atmosphere. In some examples, the suction is generated by one or more flow control element of the de-bubbler device 102, such as an impeller described in more detail below.

In some examples, a rotational speed (RPM) of the de-bubbler device 102 in use is held constant. In other examples, the rotational speed of the de-bubbler device 102 varies in use within a range 1-120 RPM. In some examples, movement of the de-bubbler device 102 while rotating or stationary includes an axial movement of the de-bubbler device 102 toward or away from the resistive element 119. In some examples, this axial movement is rapid within a range 1-120 reciprocations (each way) per minute.

In some examples, sequential periodic rotational movements, or one or more “clocked” rotational movements of the de-bubbler device 102, serves to position, in a given clocked position, one or more flow generation or flow control elements of the de-bubbler device 102 (such as a rib thereof), adjacent one or more flow control elements of the resistive element 119 (such as a restriction opening, or an aperture of the resistive element 119). This opposed or clocked configuration of respective flow control elements may serve to direct, balance, or constrain a flow of the plating solution in a desired direction, for example through a portion the resistive element 119, or to other parts of the plating cell 103. A clocked rotational movement of the de-bubbler device 102 may include unidirectional or bidirectional clocking steps, or a combination of one or more clocking steps in either direction.

The example system configuration described above is an illustration of but one embodiment of the present disclosure. Those skilled in the art will appreciate that alternative plating cell configurations that include an appropriately positioned second cathode may be used. While shielding inserts are useful for improving plating uniformity, in some embodiments they may not be required, or alternative shielding configurations may be employed. In the described configuration the plating vessel and the primary anode are substantially coextensive with the wafer substrate. In other embodiments, the diameter of the plating vessel and/or of the primary anode may be smaller than the diameter of the wafer substrate, e.g., at least about 5% smaller.

FIG. 2 illustrates the underside an example de-bubbler device 202 for use in an electroplating apparatus, for example the electroplating apparatus of FIG. 1 for depositing a metal layer on a substrate. As discussed above, an example electroplating apparatus may comprise a plating cell to receive a plating solution, an electrode, a counter electrode, substrate holding fixture, and a resistive element. In some examples, the electroplating apparatus further includes a de-bubbler device 202 supportable rotatably adjacent the resistive element, for example a resistive element 119, to generate or direct a flow of plating solution through the resistive element. In some examples, the de-bubbler device 202 is rotatable in use to generate an upward flow of plating solution through the resistive element to remove bubbles trapped thereunder. In some examples, the de-bubbler device is mountable in the substrate holding fixture, for example the substrate holding fixture, or clamshell holding fixture 107.

In some examples, the de-bubbler device 202 is generally configured or dimensioned to fit into and be held by the clamshell holding fixture 107 such that it can be rotated in use in the same manner as a substrate. To that end, in some examples, the de-bubbler device 202 includes a support structure, such as thin, wafer-shaped plate 204, for example as illustrated in FIG. 2 . In some examples, the de-bubbler device 202 includes a flow generation element 206. In some examples, the flow generation element 206 is supported by the wafer-shaped plate 204. In some examples, the flow generation element 206 includes a curved impeller 206, for example as illustrated. In the illustrated example, the impeller is an integrally-formed impeller including two curved arms 208 which serve in use as impeller blades to generate a zone of suction above a resistive element 119 and cause a suction or upward flow of plating solution through the resistive element 199, as described above. Other configurations of support structure or flow generation elements are possible, for example as shown in FIGS. 3-6 , described further below.

An example de-bubbler device 302 illustrated in FIG. 3 includes a support structure such as a thin, wafer-shaped plate 304. An underside of the wafer-shaped plate 304. The wafer-shaped plate 304 is configured and sized to be supported in use by a clamshell holding fixture 107 of an electroplating apparatus. In the illustrated example, the wafer-shaped plate 304 supports a flow generation element 306. In the illustrated example, the flow generation element 306 includes three curved impeller arms or blades 308, as shown for example. A distal end 310 of each impeller blade 308 is positioned at or adjacent a periphery of the wafer-shaped plate 304. In some examples, this outwardly extensive configuration of the impeller blades 308 serves to maximize upward suction forces generated by the blades 308 when rotating, as well as maximizing the size of a swept “clearance area” of bubbles trapped underneath a resistive element 119. In some examples, a flow generation element 306 includes one or more reinforcement elements 312. In the illustrated example, three reinforcement elements 312 are provided, one for each impeller blade 308. A reinforcement element 312 may serve to maintain or configure a profile of a flow generation element 306. In some examples, a reinforcement element 312 is configured to boost upward flow of plating solution, for example by presenting an increased surface area of an impeller blade 308 acting on the plating solution.

FIGS. 4-5 illustrate respective undersides of further examples of de-bubbler devices 402 and 502. Corresponding parts of de-bubbler devices 402 and 502 labelled similarly to those illustrated in FIGS. 2-3 . In FIG. 4 , flow generation elements 406 include a series of alternating curves, or a sinusoidal-type form, as shown. Six flow generation elements 406 are provided. The flow generation elements 406 may be supplemented by one or more linear flow generation elements 408, as shown. In some examples, the flow generation elements 408 may function as flow control elements. The supplementary linear flow generation elements 408 may include one or more ribs that stand proud of the underside of the wafer-shaped plate 404, as shown. The curved (non-linear) flow generation elements 406 and the supplementary linear flow generation (or control) elements 408 may be included or grouped into one or more flow-generation sections. A flow-generation section may include a wedge-shaped zone 410, as shown in FIG. 4 . A wedge-shaped zone 410 may include a bubble-clearing area which increases in size in an outward radial direction of the de-bubbler device 402, as shown.

In some examples, a de-bubbler device includes one or more flow control elements. A flow control element may serve to assist in directing plating solution caused to move by a flow generation element. In the example de-bubbler device 402 illustrated in FIG. 4 , a flow control element includes a channel 412 disposed between adjacent flow-generation sections 410. In this example, six such channels 412 are provided, one between each flow-generation section 410 of the de-bubbler device 402. Other configurations of flow-generation sections, flow generation elements, and flow control elements, are possible. Such configurations may serve to boost plating solution flow or bubble clearance areas.

For example, in the example de-bubbler device 502 of FIG. 5 , flow generation elements include a series of inclined, linear “mini” ribs 506. In some examples, the ribs 506 may include linear or curved sections. In this instance, the ribs 506 are linear and inclined (as shown) at an offset angle to a radial direction of the de-bubbler device 502. In some instances, the degree of offset angle increases or decreases (or alternates between degrees of offset) in a radial direction of the de-bubbler device 502. In the example illustrated in FIG. 5 , an innermost rib 506A is substantially aligned with a radial direction of the de-bubbler device 502, whereas an outermost rib 506B has a high degree of offset to the radial direction. The change in degree of the offset angle may serve to boost or direct a flow of plating solution in a given direction, or in some examples provide a zone of increased suction in one or more designated bubble clearance or flow-generation areas of a resistive element 119.

The example de-bubbler device 602 of FIG. 6 , includes a wafer-shaped plate 604 which supports one or more flow generation and flow control elements, for example as shown. An example de-bubbler device configuration may include a plurality of flow generation elements provided, for example, in an arrangement of linear ribs 608 that stand proud of the underside of the wafer-shaped back plate 604. In one example, the linear ribs 608 are arranged in a cross-hatch pattern, substantially as shown. The arrangement of ribs 608 in the cross-hatch pattern can include a number of rib crossing or rib joinder points 609 and a number of rectilinear recesses 610 defined between adjacent ribs. The linear ribs 608 extend fully across the de-bubbler device 602 between peripheral positions on the back plate.

An example flow control element may include a linear cross-rib or baffle 606 that extends across a portion of the de-bubbler device 602 between peripheral positions of the de-bubbler device 602, substantially as shown. In some electroplating operations, a resistive element 119, or a de-bubbler device (202-602), or all of these parts, may be subject to cross-flows of plating solution, as shown by the arrows 612 in use. In some examples, a baffle 606 can serve to direct, resist, or boost flow of plating solution in one or more of these cross-flow directions 612, or other desired directions. This flow-influencing action of the baffle 606 can improve plating efficiency or plating rates, for example.

As mentioned further above, an example resistive element 119 may include its own respective flow control elements. These flow control elements may include restrictions, flow focusing elements, or mini-cells for guiding, holding, or restraining plating solution through the resistive element 119, or more generally within in the plating cell 103. In one aspect of the present disclosure, the constrictive nature of some or all of these flow control elements can cause obstruction of bubbles. In some examples, a clocked rotational movement of a dc-bubbler device such as the de-bubbler device 602 of FIG. 6 serves to position, in a given clocked position, one or more flow control elements of a de-bubbler device (such as a cross-rib or baffle 606 of the de-bubbler device, FIG. 6 ), adjacent one or more flow control elements of a resistive element 119. This “matched” or “clocked” configuration of opposed flow control elements may serve to direct, balance, or constrain a flow of the plating solution in a desired manner, for example through a portion the resistive element 119, or to other parts of the plating cell 103. A clocked rotational movement of the de-bubbler device 102 may include unidirectional or bidirectional clocking steps, or a combination of one or more clocking steps in either direction.

An example configuration of a clocked position of a de-bubbler device is shown in FIG. 7 . Here, a de-bubbler device 702 is held and supported by a holding fixture such as a clamshell 707. The de-bubbler device 702 includes flow control elements, here in the form of cross-ribs or strips 706. The cross-ribs 706 may include the general configuration of a baffle 606 of FIG. 6 . Other examples may include different or further configurations of flow control elements. The de-bubbler device 702 is supported by the clamshell 707 adjacent a resistive element 719 and rotated into a given clocked position, for example as shown. The resistive element 719 includes one or more flow control elements of its own, for example a series of flow focusing elements 710. In the clocked position, a cross-rib 706 of the de-bubbler device 702 is held stationary (immobile) to lie adjacent a flow focusing element 710 of the resistive element 719, as shown. The interaction of the opposed cross-rib 706 and the flow focusing element 710 serves to create or direct a flow of the plating solution, as shown for by the arrows 712.

With reference to FIG. 8 , some examples of the present disclosure include methods of de-bubbling electroplating apparatus for depositing a metal layer on a substrate, the electroplating apparatus including a plating cell, a substrate holding fixture, a resistive element, and a de-bubbler device. A method 800 may include, at operation 802, introducing plating solution into the plating cell; at operation 804, supporting a substrate in the substrate holding fixture; at operation 806, depositing a metal layer on the substrate using the resistive element; and at operation 808, generating an upward flow of plating solution through the resistive element using the de-bubbler device to release bubbles trapped under the resistive element. In some examples, an operation 810 includes mounting the de-bubbler device in the substrate holding fixture, and rotating the de-bubbler device to generate the upward flow. In some examples, an operation 812 includes advancing or retreating the de-bubbler device towards or away from the resistive element while rotating the de-bubbler device.

FIG. 9 is a block diagram illustrating an example of a machine or controller 900 by which one or more example embodiments described herein may be implemented or controlled. In alternative embodiments, the controller 900 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the controller 900 may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the controller 900 may act as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. Further, while only a single controller 900 is illustrated, the term “machine” (controller) shall also be taken to include any collection of machines (controllers) that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as via cloud computing, software as a service (SaaS), or other computer cluster configurations. In some examples, and referring to FIG. 9 , a non-transitory machine-readable medium includes instructions 924 that, when read by a controller 900, cause the controller 900 to control operations in methods comprising at least the non-limiting example operations described herein.

Examples, as described herein, may include, or may operate by logic, a number of components, or mechanisms. Circuitry is a collection of circuits implemented in tangible entities that include hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time and underlying hardware variability. Circuitries include members that may, alone or in combination, perform specified operations when operating. In an example, hardware of the circuitry may be immutably designed to carry out a specific operation (e.g., hardwired). In an example, the hardware of the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including a Computer-Readable Medium physically modified (e.g., magnetically, electrically, by moveable placement of invariant massed particles, etc.) to encode instructions of the specific operation. In connecting the physical components, the underlying electrical properties of a hardware constituent are changed (for example, from an insulator to a conductor or vice versa). The instructions enable embedded hardware (e.g., the execution units or a loading mechanism) to create members of the circuitry in hardware via the variable connections to carry out portions of the specific operation when in operation. Accordingly, the Computer-Readable Medium is communicatively coupled to the other components of the circuitry when the device is operating. In an example, any of the physical components may be used in more than one member of more than one circuitry. For example, under operation, execution units may be used in a first circuit of a first circuitry at one point in time and reused by a second circuit in the first circuitry, or by a third circuit in a second circuitry, at a different time.

The machine (e.g., computer system) controller 900 may include a hardware processor 902 (e.g., a central processing unit (CPU), a hardware processor core, or any combination thereof), a GPU 932 (graphics processing unit), a main memory 904, and a static memory 906, some or all of which may communicate with each other via an interlink 918 (e.g., a bus) The controller 900 may further include a display device 908, an alphanumeric input device 910 (e.g., a keyboard), and a UI navigation device 912 (e.g., a mouse or other user interface). In an example, the display device 908, alphanumeric input device 910, and UI navigation device 912 may be a touch screen display. The controller 900 may additionally include a mass storage device 914 (e.g., drive unit), a signal generation device 916 (e.g., a speaker), a network interface device 920, and one or more sensors 930, such as a Global Positioning System (GPS) sensor, compass, accelerometer, or another sensor. The controller 900 may include an output controller 928, such as a serial (e.g., universal serial bus (USB)), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, card reader, etc.).

The mass storage device 914 may include a machine-readable medium 922 on which is stored one or more sets of data structures or instructions 924 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 924 may as shown also reside, completely or at least partially, within the main memory 904, within the static memory 906, within the hardware processor 902, or within the GPU 932 during execution thereof by the controller 900. In an example, one or any combination of the hardware processor 902, the GPU 932, the main memory 904, the static memory 906, or the mass storage device 914 may constitute the machine-readable medium 922.

While the machine-readable medium 922 is illustrated as a single medium, the term “machine-readable medium” may include a single medium, or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 924.

The term “machine-readable medium” may include any medium that can store, encode, or carry instructions 924 for execution by the controller 900 and that cause the controller 900 to perform any one or more of the techniques of the present disclosure, or that can store, encode, or carry data structures used by or associated with such instructions 924. Non-limiting machine-readable medium examples may include solid-state memories, and optical and magnetic media. In an example, a massed machine-readable medium comprises a machine-readable medium 922 with a plurality of particles having invariant (e.g., rest) mass. Accordingly, massed machine-readable media are not transitory propagating signals. Specific examples of massed machine-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The instructions 924 may further be transmitted or received over a communications network 926 using a transmission medium via the network interface device 920.

Although examples have been described with reference to specific example embodiments or methods, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.

Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. 

What is claimed is:
 1. An electroplating apparatus for depositing a metal layer on a substrate, the electroplating apparatus comprising: a plating cell to receive a plating solution; an electrode; a counter electrode; a substrate holding fixture; a resistive element; and a de-bubbler device supportable rotatably adjacent the resistive element to generate or direct a flow of plating solution through the resistive element.
 2. The electroplating apparatus of claim 1, wherein the de-bubbler device is rotatable in use to generate an upward flow of plating solution through the resistive element to remove bubbles trapped thereunder.
 3. The electroplating apparatus of claim 1, wherein the dc-bubbler device is mountable in the substrate holding fixture.
 4. The electroplating apparatus of claim 3, wherein the de-bubbler device includes a wafer-shaped plate.
 5. The electroplating apparatus of claim 1, wherein the de-bubbler device includes a flow generation element.
 6. The electroplating apparatus of claim 5, wherein the flow generation element includes an impeller.
 7. The electroplating apparatus of claim 1, wherein the de-bubbler device includes a flow control element.
 8. The electroplating apparatus of claim 7, wherein the flow control element includes a cross-rib.
 9. A method of de-bubbling electroplating apparatus for depositing a metal layer on a substrate, the electroplating apparatus including a plating cell, a substrate holding fixture, a resistive element, and a de-bubbler device, the method comprising: introducing plating solution into the plating cell; supporting a substrate in the substrate holding fixture; depositing a metal layer on the substrate using the resistive element; and generating an upward flow of plating solution through the resistive element using the de-bubbler device to release bubbles trapped under the resistive element.
 10. The method of claim 9, wherein generating an upward flow of plating solution through the resistive element includes mounting the de-bubbler device in the substrate holding fixture, and rotating the de-bubbler device to generate the upward flow.
 11. The method of claim 10, wherein rotating the de-bubbler device includes clocking the de-bubbler device into a clocked position with respect to the resistive element.
 12. The method of claim 10, further comprising advancing or retreating the de-bubbler device towards or away from the resistive element while rotating the de-bubbler device.
 13. A de-bubbler device for de-bubbling electroplating apparatus, the de-bubbler device comprising: a back plate, and at least one flow generation element, or at least one flow control element.
 14. The de-bubbler device of claim 13, wherein the back plate is wafer-shaped and the de-bubbler device is mountable in a substrate support fixture of the electroplating apparatus.
 15. The de-bubbler device of claim 14, wherein the at least one flow generation element includes an impeller.
 16. The de-bubbler device of claim 15, wherein a distal end of the impeller is disposed at or adjacent a periphery of the back plate.
 17. The de-bubbler device of claim 13, wherein the at least one flow control element includes a rib.
 18. The de-bubbler device of claim 13, wherein the electroplating apparatus includes a resistive device, and wherein the at least one flow control element of the de-bubbler device is configured to interact with a flow control element of the resistive device in a clocked position of the de-bubbler device.
 19. The de-bubbler device of claim 13, wherein the at least one flow control element extends fully across the de-bubbler device between peripheral positions on the back plate.
 20. The de-bubbler device of claim 13, further comprising a plurality of flow control elements, each flow control element associated with a corresponding, clocked position of the de-bubbler device.
 21. A de-bubbler device for de-bubbling electroplating apparatus, the de-bubbler device comprising: a back plate, the back plate having a wafer-shaped configuration enabling the de-bubbler device to be mounted in a substrate support fixture of the electroplating apparatus; an arrangement of flow generation elements including a plurality of linear ribs arranged in a cross-hatch pattern, each linear rib extending between peripheral locations of the back plate and standing proud of an underside of the back plate, the cross-hatch pattern of linear ribs including a plurality of rib joinder points and a plurality of rectilinear recesses disposed between adjacent ribs; and a plurality of flow elements, each flow control element including a linear baffle extending between peripheral locations of the back plate, the linear baffle configured to lie adjacent an opposed flow control element of a resistive element in a clocked position of the de-bubbler device in an electroplating apparatus. 